The Folder Tree is a common user-interface both for navigation and representing the folder hierarchy of the file system.
Normally, there is one file display and one tree. In a dual-display Lister, there are two file displays, but you have the option of using one or two trees. If you have two trees then each file display has its own - but a single tree can be shared by both file displays. In this mode, the tree will change to display the location of the active, or source, file display, and clicking on a folder in the tree will only change the location of the source file display).
Navigating using the tree is as simple as clicking on a folder; the file display attached to that tree will instantly change location to display the contents of the folder you clicked on.
If the folder tree has input focus (i.e. if it is the active user-interface element in the Lister, and keystrokes are directed to it), then it's also possible to navigate with the keyboard using the cursor keys.
The folder tree supports several keyboard commands by default:
Using the Customize system it's also possible to program your own keys that work specifically on the folder tree. Some of these are configured by default:
The small glyph displayed to the left of each item in the folder tree is known as the expansion button. If you're using a different version of Windows or a third-party theme, this may look different to the screenshot above, but in general the glyph has two main states - open and closed.
In the above screenshot, the Desktop, This PC and Local Disk branches are open - the folders have been expanded, and their child folders in the hierarchy are visible. The other branches are closed - their sub-folders are not displayed. The Logs and PerfLogs branches don't show a glyph at all - this indicates that the folders have no sub-folders, and so can't be expanded.
As in other programs, you can access the context menu for an item in the tree by right-clicking on it. From the keyboard, you can press Shift+F10 to display the context menu for the selected item. Some keyboards also have a dedicated key to the right of the space bar for this.
You can use the folder tree to rename folders (those that support being renamed, anyway). This can be activated in several ways:
Push Enter to apply the current folder's new name or Esc to cancel renaming the current folder.
In Opus the rename field has some features not found in Explorer:
You can copy or move files to folder in the tree using drag and drop. You can also drag folders out of the tree to copy or move (or create shortcuts to) them.
The title bar has a number of buttons to help work with the folder tree.
From left to right they are:
There's also an option in Preferences to enable a lock button in the title bar. When locked the tree stops following the file display around, and won't change location automatically.
The tree can be configured to highlight the path to the currently selected folder as a visual aid. It can make the current selection in the folder tree much more conspicuous. The highlight can be displayed all the time, or only when the tree itself is active.
Additionally, as in the screenshot above, the path to all currently open tabs can optionally be displayed as well. These options are all configured on the Folder Tree / Appearance page in Preferences.